Balloon catheters, with or without stents, are used to treat strictures, stenoses, or narrowings in various parts of the human body. Devices of numerous designs have been utilized for angioplasty, stents and grafts or combination stent/grafts. Varied catheter designs have been developed for the dilatation of stenoses and to deliver prostheses to treatment sites within the body lumen.
Illustrative procedures involving balloon catheters include percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA), which may be used to reduce arterial build-up such as caused by the accumulation of atherosclerotic plaque. These procedures involve passing a balloon catheter over a guidewire to a stenosis with the aid of a guide catheter. The guidewire extends from a remote incision to the site of the stenosis, and typically across the lesion. The balloon catheter is passed over the guidewire, and ultimately positioned across the lesion.
Once the balloon catheter is positioned appropriately across the lesion, (e.g., under fluoroscopic guidance), the balloon is inflated, which breaks the plaque of the stenosis and causes the arterial cross section to increase. Then the balloon is deflated and withdrawn over the guidewire into the guide catheter, and from the body of the patient.
In many cases, a stent or other prosthesis must be implanted to provide support for the artery. When such a device is to be implanted, a balloon catheter which carries a stent on its balloon is deployed at the site of the stenosis. The balloon and accompanying prosthesis are positioned at the location of the stenosis, and the balloon is inflated to circumferentially expand and thereby implant the prosthesis. Thereafter, the balloon is deflated and the catheter and the guidewire are withdrawn from the patient.
Administering PTCA and/or implanting a stent at a bifurcation in a body lumen poses further challenges for the effective treatment of stenoses in the lumen. For example, dilating a main vessel at a bifurcation may cause narrowing of the adjacent branch vessel. In response to such a challenge, attempts to simultaneously dilate both branches of the bifurcated vessel have been pursued. These attempts include deploying more than one balloon, more than one prosthesis, a bifurcated prosthesis, or some combination of the foregoing. However, simultaneously deploying multiple and/or bifurcated balloons with or without endoluminal prostheses, hereinafter individually and collectively referred to as a bifurcated assembly, requires accurate placement of the assembly. Deploying multiple stents requires positioning a main body within the main vessel adjacent the bifurcation, and then attempting to position another stent separately into the branch vessel of the body lumen. Alternatives to that include deploying a dedicated bifurcated stent including a tubular body or trunk and two tubular legs extending from the trunk. Some examples include U.S. Pat. No. 5,723,004 to Dereume et al., U.S. Pat. No. 4,994,071 to MacGregor, and U.S. Pat. No. 5,755,734 to Richter et al.
Additional bifurcation stent delivery systems that provide improved reliable treatment at bifurcations are disclosed, for example, in U.S. Pat. No. 6,325,826 to Vardi et al. and U.S. Pat. No. 6,210,429 to Vardi et al. The contents of the '826 and '429 patents are incorporated herein by reference.
A need still exists for further improved devices and techniques for treating a bifurcated body lumen. For example, a need further exists for additional stent delivery systems that can be used with stents having a branch access side hole and/or an extendible branch portion.
The present invention is directed to devices and techniques for treating a bifurcated body lumen including systems for delivering an endoluminal prosthesis at or near a bifurcation of a body lumen. Systems, devices and techniques are disclosed comprising balloon catheters configured to successfully and reliably deploy stents at a bifurcation in a body lumen. Additionally, the balloon catheters can be employed as balloon angioplasty catheters to treat occlusions in blood vessels such as for instance in percutaneous transluminal coronary angioplasty (PTCA) procedures.
According to one aspect, the present invention provides a catheter assembly for use in bifurcated vessels. The assembly includes an elongated catheter body having a proximal end and a distal end and a balloon associated with the distal end of the balloon catheter. The balloon includes a main vessel balloon for treating a main vessel of the bifurcation, and a branch vessel balloon for treating a branch vessel of the bifurcation. The branch vessel balloon includes an accordion configuration capable of being expanded from an unexpanded collapsed accordion configuration to an expanded accordion configuration extending into the branch vessel.
According to another aspect, the branch vessel balloon includes accordion folds and the folds are substantially collapsed against each other in the unexpanded configuration, and separated from each other in the expanded configuration.
In another aspect, the catheter assembly includes a bifurcated stent, which is disposed on the balloon. In particular, the present invention provides a catheter assembly including a bifurcated stent, which has a main vessel portion and an extendible branch vessel portion. The branch vessel balloon is disposed substantially adjacent the extendible branch portion. Upon expansion, the branch vessel balloon expands the extendible branch vessel portion of the stent into the branch vessel.
In another aspect of the invention, the catheter includes an inflation lumen, and the balloon has an interior in fluid communication with the inflation lumen. More particularly, the inflation lumen comprises two inflation lumens. The first inflation lumen is in fluid communication with the interior of the branch vessel balloon. The second inflation lumen is in communication with an interior of the main vessel balloon.
In another aspect of the invention, the branch and main vessel balloons described above comprise a unitary balloon, and in other embodiments, the branch vessel balloon is separate from the main vessel balloon.
According to another aspect, the present invention provides a catheter assembly, which includes a side sheath associated with the elongated catheter body. At least a portion of the side sheath extends along the distal end of the catheter body and adjacent the branch vessel balloon. In some aspects of the invention, the branch vessel balloon is disposed on the side sheath. In another aspect of the invention, the side sheath is disposable in the branch vessel. Additionally, the main vessel balloon is disposable in the main vessel during placement of the catheter assembly in a bifurcated vessel. The accordion configuration can be oriented to expand in a direction substantially perpendicular to a longitudinal axis of the main vessel balloon. In a further aspect of the invention, the branch vessel balloon is located on the side sheath and oriented to expand in a direction substantially parallel to a longitudinal axis of the side sheath.
In another aspect, the branch vessel balloon comprises a herniation on the main vessel balloon, and in another aspect, the present invention provides a catheter assembly which includes a side sheath. One end of the branch vessel balloon is slidably affixed to the side sheath.
According to an additional aspect, the profile of the accordion folds of the catheter assembly of the present invention is substantially either round, elliptical, square, hexagonal or octagonal when viewed along the direction of inflation. Additionally, in other aspects, the profile of the accordion folds is substantially triangular or round when viewed perpendicularly to the direction of inflation.
In a further aspect of the invention, the accordion configuration includes a plurality of fluidly connected cells connected in series. The series defines an axis of primary inflation. In another embodiment, the successive cells have a different size from the preceding cells in the series. In a further aspect, the cells are adapted to merge into a substantially tubular structure when fully expanded.
According to yet another aspect, the present invention provides a catheter assembly for use in bifurcated vessels. The assembly includes an elongated catheter body having a proximal end and a distal end and a balloon associated with the distal end of the balloon catheter. The balloon includes a main vessel balloon for treating a main vessel of the bifurcation and a branch vessel balloon for treating a branch vessel of the bifurcation. The branch vessel balloon comprises a plurality of fluidly connected cells connected in series, the series defining an axis of primary inflation. When the branch vessel balloon is expanded, expansion along the axis of primary inflation is greater than expansion in a radial direction, which is substantially perpendicular to the axis of primary inflation.
A further aspect of the present invention provides a catheter assembly having successive cells, which differ in size from the preceding cells in the series. In another aspect, the cells are adapted to merge into a substantially tubular structure when fully expanded.
According to another aspect, the present invention provides a method of treating a bifurcation of a body lumen. The bifurcation includes a main vessel and a branch vessel. The method includes introducing a balloon and stent assembly into the main vessel, the balloon having at least one accordion inflation portion, wherein the accordion inflation portion comprises a plurality of accordion folds; positioning the assembly at the bifurcation; and inflating the balloon to expand the stent in the main vessel.
A further aspect of the invention provides a method of treating a bifurcation of a body lumen in which the step of inflating includes expanding a portion of the stent outwardly toward the branch vessel. Another aspect provides a method in which the accordion configuration expands the portion of the stent outwardly toward the branch vessel. The body lumen described above can be a blood vessel.